The drug hasn't been shown to be an effective treatment for COVID-19.
Early on in the pandemic, ivermectin was one drug some doctors tested to see if it could be repurposed as a COVID-19 treatment. The antiparasitic had seemingly positive effects on some patients, however, more studies showed it had little to no effect when it comes to treating the disease. One new study in Japan is being touted by COVID misinformation peddlers as proof of ivermectin's effectiveness, but that's not the case.
A study from Japanese trading and pharmaceuticals company Kowa found ivermectin did have an "antiviral effect" on the SARS-CoV-2 virus, according to a Monday report from Reuters that was later corrected. What wasn't made clear in the initial story was that this effect was already known, and limited to "joint nonclinical research," meaning it showed that effect in test tubes. Ivermectin still hasn't shown any effectiveness in treating COVID.
Here's what you need to know about ivermectin.
Ivermectin is an antiparasitic medicine that cures diseases such as river blindness and scabies by paralyzing and killing the parasites. It can also inhibit some viruses from infecting cells, thus preventing the virus from spreading, like with dengue fever.
The drug isn't common in the US. There were 146,212 prescriptions written for ivermectin in 2019, according to the drug database ClinCalc. In comparison, the cholesterol-lowering atorvastatin, better known under the brand name Lipitor, hit 112 million prescriptions that same year. Ivermectin was primarily prescribed as a lotion, which is common to treat lice and scabies.
Where ivermectin is used more frequently is in developing countries where parasites are more common and deadlier.
"Ivermectin provides significant health benefits in treating parasitic diseases, especially in areas of extreme poverty in low middle-income countries," said Dr. Gerald W. Parker, associate dean for Global One Health, College of Veterinary Medicine and Biomedical Sciences at Texas A&M University.
Scientists at pharmaceuticals giant Merck discovered ivermectin in 1975 and began using it in 1981 to treat scabies, river blindness and other parasitic diseases carried by worms and lice. It's on the World Health Organization's list of essential medicines for a basic health care system. More than 250 million people take the drug across the globe each year, and it's effective for animals as well. The researcher who developed ivermectin received the Nobel Prize in 2015.
The drug is considered safe when taken in appropriate dosages. Side effects for ivermectin vary depending on whether it's taken orally to treat intestinal infections or topically for skin infections. Oral tablets can cause drowsiness, nausea, vomiting and, in very rare cases, an increase in heart rate and the onset of seizures. Side effects for the topical ivermectin can include skin rash and irritation, while dry skin and stinging pain are severe and rare.
The US Food and Drug Administration, the National Institutes of Health, the World Health Organization and other agencies don't suggest ivermectin's use to treat COVID-19. They cite the lack of data from large, randomized trials confirming the drug's effectiveness to treat the disease.
Some doctors who cite multiple smaller studies and firsthand experience say otherwise. They claim ivermectin does work to prevent people from developing symptoms from COVID-19 and can shorten recovery time for those already infected. Many of those studies, however, have issues because of small numbers of participants, poor methodology or flawed data.
The discussion isn't new. The FDA said in March 2021 that it hadn't approved the use of ivermectin to treat COVID-19. It warned that large doses of the drug are "dangerous and can cause serious harm." The agency also advised against the human use of ivermectin produced for animals, such as cows and horses, as the doses aren't the same and could contain ingredients intended only for animals.
However, as the delta variant created yet another wave of the pandemic this summer, a growing number of people began taking ivermectin intended for animals as word spread on social media about the medication's possible use against COVID-19. That's despite public health experts warning people against it because it's dangerous.
The use of livestock ivermectin has resulted in some people calling state poison centers after taking the drug and experiencing negative and sometimes disturbing side effects. In August, the Mississippi State Department of Health sent out an alert regarding the number of calls its poison center received, with 70% related to the "ingestion of livestock or animal formulations of ivermectin purchased at livestock supply centers." Similar stories came from other states, including Oklahoma, Utah and Alabama, where poison centers have been receiving more calls from people who took too much of the drug. There were also two deaths linked to ivermectin, as confirmed by the New Mexico Department of Health.
The FDA reaffirmed in a post published in April on its website that ivermectin isn't approved to treat COVID-19 nor has it been given emergency use authorization. Then in August, it tried a different approach to get people's attention, tweeting: "You are not a horse. You are not a cow. Seriously, y'all. Stop it."
The NIH said in February 2021 that there was insufficient data to "recommend either for or against the use of ivermectin for the treatment of COVID-19." It did say lab tests found the drug stopped the reproduction of the SARS-CoV-2 virus that causes the disease. However, to be effective, the dosages would need to be "100-fold higher than those approved for use in humans."
While some clinical studies showed ivermectin to have no benefit, the NIH said other studies saw a lower mortality rate among patients. However, those studies were incomplete or had methodological limitations such as small sample sizes or patients receiving additional medicine along with ivermectin, according to the NIH.
The World Health Organization said in March that the current evidence on the use of ivermectin for treatment of COVID-19 was "inconclusive."
The American Medical Association, American Pharmacists Association and American Society of Health-System Pharmacists say they "strongly oppose the ordering, prescribing, or dispensing of ivermectin to prevent or treat COVID-19 outside of a clinical trial."
Ivermectin's potential use as a COVID-19 therapeutic made headway in December 2020 during a US Senate Homeland Security Committee meeting called Focus on Early Treatment of COVID-19. Dr. Pierre Kory, a pulmonary and critical care specialist, testified about the drug's use for the treatment of the disease. But there were several problems with the information he cited.
"Ivermectin is highly safe, widely available, and low cost," Kory said in the Senate meeting. "We now have data from over 20 well-designed clinical studies, 10 of them randomized, controlled trials, with every study consistently reporting large magnitude and statistically significant benefits in decreasing transmission rates, shortening recovery times, decreasing hospitalizations, or large reductions in deaths. These data show that ivermectin is effectively a 'miracle drug' against COVID-19."
During his testimony, Kory referred to a paper he authored -- Review of the Emerging Evidence Demonstrating the Efficacy of Ivermectin in the Prophylaxis and Treatment of COVID-19 -- that was published in the May 2020 edition of the American Journal of Therapeutics.
The paper was also included in the Frontiers of Pharmacology journal in January 2021 but was then removed in March. Dr. Frederick Fenter, chief executive editor of the journal, said the paper was removed due to "strong, unsupported claims based on studies with insufficient statistical significance, and at times, without the use of control groups." Fenter also said the authors promoted their own specific ivermectin-based treatment, which goes against editorial policies.
The studies listed in Kory's paper tend to be for a small number of participants and have a questionable methodology. For example, a study of 234 uninfected health care workers in Argentina found those who received the drug were far less likely to be diagnosed with COVID. A BuzzFeed News report was unable to find confirmations that this trial even occurred as the hospital it purportedly was conducted in says its health care workers weren't included in a test.
An Iraq study saw a quicker recovery time with using ivermectin, but the test was done on only 70 patients. In a small double-blind, randomized placebo-controlled trial in Israel with a group of 89 patients, those taking ivermectin saw lower viral loads than those who didn't receive the drug.
There are also studies that show otherwise. A clinical trial of 476 patients found ivermectin didn't improve the recovery time in patients who had COVID-19. A review of 10 random clinical trials, with more than 1,000 participants, also didn't find improvements with ivermectin. One Egyptian study claimed to show positive results, but it's since been redacted over ethical concerns. Another study, of 1,500 patients, found that ivermectin had "no effect whatsoever."
One thing to note is that many of these studies have yet to be peer-reviewed.
Merck, the company that created ivermectin, released a statement in February 2021 saying there was "no scientific basis for a potential therapeutic effect against COVID-19 from pre-clinical studies" and "no meaningful evidence for clinical activity or clinical efficacy in patients with COVID-19 disease." It also cited a lack of safety data from major studies.
The debate about ivermectin's usage to treat COVID-19 has gone from the hospital to social media, exacerbating the discourse as well as the vitriol. While those in support of the drug appear to want an end to the pandemic, their arguments in favor of ivermectin have become fodder for anti-vaccine activists and conspiracy theorists.
COVID vaccines have been shown to decrease the chance of hospitalization and death. According to the CDC in January, individuals who received a booster shot were 68 times less likely to die than those unvaccinated.
Groups that have spread misinformation about COVID-19 throughout the pandemic latched onto ivermectin's use following Kory's Senate testimony. Anti-vaccine groups on social media and messaging app Telegram share misinformation about the vaccine while asking where they can buy the drug. Rumble, an alternative video platform to YouTube, has pages of videos falsely saying vaccines are ineffective while advising people to take ivermectin.
Anti-vaccine posts and videos can also be found on YouTube, Facebook and Twitter, though the companies are attempting to take these posts down or make them harder to find.
Kory was a guest on the Dark Horse Podcast hosted by Bret Weinstein, a former professor at Evergreen State College, in June 2021 to talk about ivermectin. That video was eventually demonetized on YouTube and Weinstein's channel received a strike, which prevented him from posting content for one week and could have led to its removal if he received two more strikes within 90 days.
YouTube says its actions on Weinstein's videos were part of its policies.
"While we welcome open discussions of potential treatments and clinical trials related to COVID-19 on YouTube, based on guidance from the CDC, FDA and other local health authorities, we don't currently allow content that recommends ivermectin as an effective treatment or prevention method for the virus," said Ivy Choi, a YouTube spokesperson. "We craft our policies to prevent the risk of egregious real-world harm, and update them as official guidance evolves. We do allow exceptions to our policy about ivermectin, including content that also gives viewers the full context of the FDA's current position."
Because of YouTube's decision, the controversy over ivermectin grew and became tied to what some claim to be "big tech censorship."
Two New Mexicans died due to ivermectin, as first spotted by Albuquerque news station KOB on Sept. 22, 2021, and confirmed by the state's department of health. One of the individuals who died was reportedly battling a serious case of COVID-19.
"Drugs should only be used as directed, and ivermectin is not a viable treatment for COVID-19," said David Morgan, New Mexico Department of Health media and social media manager.
Large clinical studies are being conducted around the world.
"There is a large, ongoing randomized, placebo-controlled trial in the United Kingdom, so officially the jury is still out to see if ivermectin may offer clinical benefit," said Dr. Parker. "But so far there is no indication to use ivermectin as a patient or prescribe as a physician, other than in an approved clinical trial."
The Oxford University Principle Trial is seeking to work with more than 5,000 participants and give a three-day course of oral ivermectin treatment to individuals randomly and compare their results to individuals who receive standard care. However, the study was put on hold in December due to supply issues.
In the US, the NIH is evaluating therapeutics for COVID-19 with its Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV) master protocol. Ivermectin was added in phase three of ACTIV-6, which will test the effectiveness of repurposed drugs.
"The ACTIV prioritization group, trial team and trial oversight groups continuously track new data on any agent we are studying in our trials and evaluate that data for how it might influence our testing of that agent and the safety/well being of the participants in the trial," said Dr. Sarah Dunsmore, a program director at the National Center for Advancing Translational Sciences, which is part of the NIH.
Results for this study will be released sometime in the first quarter of 2022.
Both Merck and Pfizer have antiviral pills that were authorized by the FDA in December to treat COVID-19.